Vibrating diaphragm, sound production device and electronic equipment

Abstract

The invention discloses a vibrating diaphragm, a sound production device and electronic equipment, and relates to the acoustics field, the vibrating diaphragm comprises at least one thermoplastic polyamide elastomer layer, the thermoplastic polyamide elastomer layer comprises a thermoplastic polyamide elastomer, the thermoplastic polyamide elastomer comprises a hard segment and a soft segment, the hard segment contains an aromatic ring and an amido bond, the soft segment comprises at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane, and the size change rate of the thermoplastic polyamide elastomer layer after heat treatment at 120 DEG C for 1 h is less than or equal to 2%. The vibrating diaphragm provided by the invention can give consideration to rebound resilience and strength required by vibration, and is resistant to high temperature and easy to process.

Description

Technical Field

[0001] The present invention relates to the field of acoustics, and in particular to a diaphragm, a sound-generating device and an electronic device. Background Art

[0002] At present, the diaphragm materials used in sound-generating devices all have some shortcomings. Although engineering plastics such as PEEK (Poly Ether Ether Ketone) and PAR (Polyarylate) have good temperature resistance, the material resilience is poor. The diaphragm products are prone to membrane folding and cannot play a waterproof role. Although TPU (Thermoplastic Polyurethanes) and TPEE (Thermoplastic Elastomer) materials have certain strength and resilience, the diaphragm sometimes has insufficient temperature resistance when used in high-power sound-generating devices. Although rubber diaphragm materials, such as silicone rubber and hydrogenated nitrile rubber, have improved temperature resistance and resilience, the processing cost is too high.

[0003] Therefore, there is currently a lack of a diaphragm that can take into account resilience, high strength, high temperature resistance and easy processing. Summary of the invention

[0004] The main purpose of the present invention is to provide a diaphragm, a sound-emitting device and an electronic device, aiming to solve the technical problem that the current diaphragm cannot meet the requirements of resilience, high strength, high temperature resistance and easy processing.

[0005] To achieve the above-mentioned purpose, the present invention provides a diaphragm, which includes at least one layer of thermoplastic polyamide elastomer, the thermoplastic polyamide elastomer layer includes a thermoplastic polyamide elastomer, the thermoplastic polyamide elastomer includes a hard segment and a soft segment, wherein the hard segment contains an aromatic ring and an amide bond, and the soft segment includes at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane, and the dimensional change rate of the thermoplastic polyamide elastomer layer after heat treatment at 120°C for 1 hour is ≤2%.

[0006] In one embodiment, the hard segment comprises a semi-aromatic amide structure;

[0007] And / or, the mass proportion of the hard segment in the thermoplastic polyamide elastomer is 5 to 95%.

[0008] In one embodiment, the prepolymer of the hard segment is an aromatic amide prepolymer terminated with end groups;

[0009] Alternatively, the prepolymer of the hard segment is an amide prepolymer formed by the reaction of aromatic isocyanate and aliphatic carboxylic acid.

[0010] In one embodiment, the hard segment includes at least one of PA6T, PA4T, PA9T, PA10T, PA12T, PA6T / 6I, PA6T / 66, PA66 / 6T / 6I, PA10T, PA10I, PPTA, PMIA, PA5T, PA11T and PAMXD6.

[0011] In one embodiment, the soft segment includes at least one of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone, aliphatic polycarbonate diol, polydimethylsiloxane, polytrimethyl glycol, polyethylene oxide, polypropylene oxide diol, and polyether diamine.

[0012] In one embodiment, the softening temperature of the thermoplastic polyamide elastomer layer when the storage modulus is 6.47 MPa is greater than or equal to 130° C.;

[0013] And / or, the moisture absorption rate of the thermoplastic polyamide elastomer layer under the conditions of a temperature of 23° C. and a humidity of 50% is ≤5%.

[0014] In one embodiment, the thermoplastic polyamide elastomer layer has a thickness of 5-500 μm.

[0015] In one embodiment, the thermoplastic polyamide elastomer layer further includes at least one of a stabilizer, a capping agent, an antioxidant, an ultraviolet light absorber, a molecular weight regulator, and a catalyst.

[0016] In one embodiment, the diaphragm is formed by compression molding, air pressure molding or integral injection molding.

[0017] In one embodiment, the diaphragm is formed as a single-layer structure, and the diaphragm includes a layer of the thermoplastic polyamide elastomer;

[0018] Alternatively, the diaphragm is formed as a multilayer composite structure including the thermoplastic polyamide elastomer layer and a connecting layer, and the connecting layer includes at least one of a glue layer, a thermoplastic plastic layer, a thermoplastic elastomer layer, and a rubber layer.

[0019] The present invention also provides a sound-generating device, which includes the diaphragm as described above.

[0020] In one embodiment, the sound-generating device includes a magnetic circuit system and a vibration system, the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm are respectively arranged at the two axial ends of the voice coil, one end of the voice coil drives the first diaphragm to vibrate and produce sound, and the other end of the voice coil is connected to one end of the second diaphragm to balance the vibration of the voice coil, and the first diaphragm and / or the second diaphragm are the diaphragms described above.

[0021] The present invention further provides an electronic device, which includes the sound-generating device as described above.

[0022] The present invention provides a diaphragm, a sound-generating device and an electronic device, wherein the diaphragm comprises at least one layer of a thermoplastic polyamide elastomer layer, wherein the thermoplastic polyamide elastomer layer comprises a thermoplastic polyamide elastomer, wherein the thermoplastic polyamide elastomer comprises a hard segment and a soft segment, wherein the hard segment contains an aromatic ring and an amide bond, and the soft segment is selected from at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane, and the dimensional change rate of the thermoplastic polyamide elastomer layer after heat treatment at 120°C for 1 hour is ≤2%. The hard segment contains aromatic rings and amide bonds. The presence of aromatic rings can largely ensure the high temperature resistance and mechanical strength of the material, effectively play the role of physical cross-linking points, reduce the slippage and viscous flow between molecular chains when the diaphragm is deformed, and with the cooperation of amide bonds, the polarity of the hard segment is further increased, and the interaction between the molecular chains of the hard segment is enhanced, so that the diaphragm has better dimensional stability, weather resistance and other excellent properties. The soft segment includes at least one of polyether, polyester, polyether ester, polysiloxane, and aliphatic polycarbonate with excellent flexibility, which can provide the diaphragm with the required toughness, low temperature resistance, resilience, etc. , the soft segment and the hard segment are combined, and the thermoplastic polyamide elastomer layer shows a dimensional change rate of ≤2% after heat treatment at 120°C for 1h, which means that the thermoplastic polyamide elastomer has good dimensional stability under high temperature conditions and can withstand high temperatures. Therefore, the diaphragm provided by the present invention can combine the strength and toughness required for vibration, and at the same time has excellent properties such as good high temperature resistance and high rebound rate, which effectively solves the problems of insufficient elasticity and insufficient temperature resistance of the diaphragm in the prior art. Compared with the diaphragm made of rubber material, the diaphragm in the present invention also has the advantages of being easier to process and having low processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present drawings or related technologies, the drawings required for use in the embodiments or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 It is a cross-sectional view of the single-layer structure diaphragm involved in the present invention;

[0025] Figure 2 It is a cross-sectional view of a two-layer composite structure diaphragm according to the present invention;

[0026] Figure 3 It is a cross-sectional view of a three-layer composite structure diaphragm according to the present invention;

[0027] Figure 4 It is a cross-sectional view of another three-layer composite structure diaphragm involved in the present invention;

[0028] Figure 5 It is a cross-sectional view of an embodiment of the sound-generating device according to the present invention;

[0029] Figure 6 It is a cross-sectional view of another embodiment of the sound-generating device according to the present invention;

[0030] Figure 7 It is a storage modulus test result diagram of the embodiment of the present invention and the comparative example;

[0031] Figure 8 A schematic diagram of a vibration system of a loudspeaker according to the present invention;

[0032] Fig. 9 Graph showing high temperature life reliability test results of the embodiments of the present invention and the comparative example.

[0033] Description of reference numerals:

[0034] A, a thermoplastic polyamide elastomer layer;

[0035] B, connection layer; B1, first sub-connection layer; B2, second sub-connection layer;

[0036] 100, sound-generating device; 110, housing; 120, diaphragm;

[0037] 121, a first diaphragm; 122, a second diaphragm;

[0038] 123, folding ring; 124, ball top;

[0039] 130. Voice coil; 140. Magnetic circuit system.

[0040] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0042] An embodiment of the present invention provides a diaphragm 120, which includes at least one layer of thermoplastic polyamide elastomer layer A, wherein the thermoplastic polyamide elastomer layer A includes a thermoplastic polyamide elastomer, and the thermoplastic polyamide elastomer includes a hard segment and a soft segment, wherein the hard segment contains an aromatic ring and an amide bond, and the soft segment includes at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane, and the dimensional change rate of the thermoplastic polyamide elastomer layer A after heat treatment at 120°C for 1 hour is ≤2%.

[0043] In the present embodiment, the thermoplastic polyamide elastomer layer A is a layered material for forming a diaphragm, and the thermoplastic polyamide elastomer layer A includes a thermoplastic polyamide elastomer, which can be a block copolymer, including a hard segment and a soft segment. The hard segment contains an aromatic ring and an amide bond. Aromatic ring refers to a class of organic aromatic compounds, which have a stable aromatic ring structure, a high bond energy and a melting point. The introduction of aromatic rings in the hard segment can enhance the high temperature resistance and mechanical properties of the diaphragm. Amide bonds are the basic structure of thermoplastic polyamide elastomers, which have a high polarity. The coordination between the aromatic ring and the amide bond further increases the polarity of the hard segment, and the interaction between the hard segment molecular chains is enhanced, so that the diaphragm 120 exhibits excellent dimensional stability, as well as chemical resistance, weather resistance and other characteristics. The soft segment may include at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane. Specifically, the molecular chain of polyester usually has ester groups as repeating units, the molecular chain of polyether has ether bonds as repeating units, and the molecular chain of polyetherester contains both ester groups and ether bonds. The molecular chain of aliphatic polycarbonate contains carbonate groups, and the carbonate groups and aliphatic groups are arranged alternately. The main chain of polysiloxane is composed of silicon atoms and oxygen atoms alternately forming silicon-oxygen bond repeating units, and organic groups are connected to the silicon atoms of the main chain.

[0044] In some embodied embodiments, the hard segment includes a semi-aromatic amide structure. Amide bonds exist in the hard segment and can be formed by a condensation reaction of amino groups and carboxyl groups. When only one of the amino-containing monomer and the carboxyl-containing monomer contains an aromatic ring, polymerization forms a semi-aromatic amide structure. When both the amino-containing monomer and the carboxyl-containing monomer contain aromatic rings, a fully aromatic amide structure is formed. The semi-aromatic amide structure has good heat resistance and can take into account both the strength and toughness of the material. It is less difficult to process than the fully aromatic amide structure. Therefore, by making the hard segment include a semi-aromatic amide structure, the structural strength and toughness of the diaphragm 120 can be improved, and the processing difficulty of the diaphragm 120 can also be reduced.

[0045] In some practicable embodiments, the prepolymer of the hard segment is an aromatic amide prepolymer terminated with end groups; or, the prepolymer of the hard segment is an amide prepolymer formed by the reaction of an aromatic isocyanate and an aliphatic carboxylic acid. The aromatic amide prepolymer terminated with end groups is subjected to an end-capping treatment, and the type of its end groups is related to the end-capping agent used in the end-capping treatment. The above-mentioned aromatic amide prepolymer terminated with end groups, as well as the amide prepolymer formed by the reaction of an aromatic isocyanate and an aliphatic carboxylic acid, can form a semi-aromatic amide structure of the hard segment. Different prepolymers can be selected for polymerization according to the requirements for the type of end groups or the molecular weight in actual situations, and this embodiment does not impose specific restrictions on this. The end-capped aromatic amide prepolymer is selected, and the formed hard segment may include at least one of PA6T, PA4T, PA9T, PA10T, PA12T, PA6T / 6I, PA6T / 66, PA66 / 6T / 6I, PA10T, PA10I, PPTA, PMIA, PA5T, PA11T and PAMXD6. The type of hard segment plays a major role in the high temperature resistance of the diaphragm 120, and the hard segment structure and content can be matched according to the application scenario of the diaphragm 120.

[0046] In some practicable embodiments, the mass proportion of the hard segment in the thermoplastic polyamide elastomer is 5 to 95%, for example, 5%, 8%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, etc. The mass proportion of the hard segment in the thermoplastic polyamide elastomer directly affects the various properties of the diaphragm 120. It is understandable that when the hard segment content in the thermoplastic polyamide elastomer is too little, the strength, high and low temperature resistance and dimensional stability of the diaphragm 120 will be greatly reduced. When the hard segment content in the thermoplastic polyamide elastomer is too much, the toughness and resilience of the diaphragm 120 will be greatly reduced. In order to ensure that the diaphragm 120 can take into account the characteristics required by the diaphragm, such as good strength, toughness, resilience, high and low temperature resistance, dimensional stability, etc., the mass proportion of the hard segment is controlled to be within the range of 5 to 95%. The hard segment contains a relatively rigid aromatic ring structure and a relatively polar amide structure. The hard segment molecular chain has relatively high strength. The higher the hard segment content, the higher the strength of the diaphragm 120, but the brittleness increases. In order to ensure that the diaphragm 120 has good strength and toughness, and in combination with the application requirements of the diaphragm 120 in the sound-generating device 100, the mass proportion of the hard segment can be further limited to 10-80%.

[0047] In some practicable embodiments, the soft segment includes at least one of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone, aliphatic polycarbonate diol, polydimethylsiloxane, polytrimethyl glycol, polyethylene oxide, polypropylene oxide diol, and polyether diamine. The chemical structure, content, molecular weight, etc. of the soft segment directly affect the flexibility, low temperature resistance, resilience, etc. of the diaphragm 120, and the soft segment combined with the hard segment can be selected according to the various performance requirements of the diaphragm 120.

[0048] In this embodiment, the dimensional change rate of the thermoplastic polyamide elastomer layer A after heat treatment at 120°C for 1 hour is ≤2%, for example, 0.5%, 1%, 1.5%, 2%, etc. The dimensions measured in this embodiment are the length and width of the diaphragm 120. The calculation of the dimensional change rate can refer to: dimensional change rate = (length before treatment - length after treatment) / length before treatment * 100%; or, dimensional change rate = (width before treatment - width after treatment) / width before treatment * 100%. Due to the strong structural strength of the hard segment, the thermoplastic polyamide elastomer overall material exhibits excellent high temperature resistance and dimensional stability, and the dimensional change rate after heat treatment at 120°C for 1 hour is not higher than 2%. The lower the dimensional change rate, the better the high temperature resistance of the diaphragm 120, and the less likely it is to deform, which can indicate that the diaphragm 120 in the present invention has good temperature resistance. If the size change rate is higher than 2%, the diaphragm 120 used in the sound-generating device 100 may have a reliability problem in that the shape of the diaphragm 120 changes significantly when used, resulting in a significant impact on the acoustic performance of the diaphragm 120 .

[0049] In some practicable embodiments, the softening temperature of the thermoplastic polyamide elastomer layer A when the storage modulus is 6.47 MPa is greater than or equal to 130°C, for example, 130°C, 140°C, 150°C, 160°C, etc. The hard segment contains an aromatic ring and an amide bond, and the intermolecular force is strong, which is macroscopically manifested in that the diaphragm 120 has high mechanical strength and high temperature resistance. The type of hard segment plays a major role in the high temperature resistance of the diaphragm 120. By matching the hard segment structure and content according to the application scenario, the softening temperature of the thermoplastic polyamide elastomer layer A is not lower than 130°C, and the softening temperature can be further achieved to be not lower than 150°C. It is understandable that when the temperature is higher than the softening temperature, the strength of the diaphragm 120 is insufficient, and it is easy to undergo irreversible deformation when subjected to external force, resulting in changes in product shape and failure of product performance. The higher the softening temperature, the better the high temperature resistance of the diaphragm 120. Since the maximum operating temperature of the sound-generating device 100 can reach 80-120°C, by controlling the softening temperature of the thermoplastic polyamide elastomer layer A to be not less than 130°C, it can be ensured that the diaphragm 120 can work normally at the operating temperature and the sound effect of the sound-generating device 100 can be ensured.

[0050] In some practicable embodiments, the moisture absorption rate of the thermoplastic polyamide elastomer layer A at a temperature of 23°C and a humidity of 50% is ≤5%, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, etc. It is understandable that the amide bond in the hard segment has a strong molecular polarity, so it is easy to generate hydrogen bonding forces and has a relatively high water absorption capacity. However, the diaphragm 120 needs to meet the performance requirements under various temperature, humidity and reliability conditions, so it has certain requirements for water absorption capacity. In order to ensure the good acoustic performance of the diaphragm 120, the moisture absorption rate of the thermoplastic polyamide elastomer layer A is controlled not to be higher than 5%, and this moisture absorption rate is tested using the ISO 62 standard at a temperature of 23°C and a humidity of 50%. Specifically, the polyester, polyether and other groups in the soft segment are groups with weak polarity. The soft segment and the hard segment are combined, so that the polarity of the thermoplastic polyamide elastomer formed after the combination is lower than that of the hard segment, the difficulty of generating hydrogen bonding forces is increased, and the water absorption capacity is reduced. By matching the hard segment structure and content with the soft segment, the moisture absorption rate of the thermoplastic polyamide elastomer layer A can be further controlled to be less than 1%, thereby allowing the diaphragm 120 to meet actual usage requirements.

[0051] In some practicable embodiments, the thickness of the thermoplastic polyamide elastomer layer A is 5 to 500 μm, for example, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, etc. It should be noted that if the thickness of the thermoplastic polyamide elastomer layer A is too thin, the stiffness of the diaphragm 120 is insufficient, the vibration is prone to polarization, and the film-making process is limited. The thinner the thickness, the higher the process cost. The thicker the thermoplastic polyamide elastomer layer A, the higher the quality of the diaphragm 120, the lower the vibration efficiency of the sound-generating device 100, and the lower the sound sensitivity. By further limiting the thickness to the range of 10 to 300 μm, the requirements for the stiffness of the diaphragm 120, the process cost, and the vibration efficiency can be taken into account.

[0052] In some practicable embodiments, the thermoplastic polyamide elastomer layer A further comprises at least one of a stabilizer, an end capping agent, an antioxidant, an ultraviolet light absorber, a molecular weight regulator and a catalyst. The connection between the soft segment and the hard segment of the thermoplastic polyamide elastomer is mainly achieved through the reaction between the end groups. For the hard segment, the end groups at both ends of the molecule include carboxyl, amino, isocyanate and acyl chloride, etc. For the soft segment, the end groups include hydroxyl, amino, isocyanate and carboxyl, etc. In the preparation process of the thermoplastic polyamide elastomer, an appropriate amount of additives such as the above-mentioned stabilizer, end capping agent, antioxidant, ultraviolet light absorber, molecular weight regulator, catalyst and other compounds can also be added according to product needs.

[0053] Stabilizer can increase the stability of thermoplastic polyamide elastomer, prevent its decomposition and aging. The stabilizer of the present embodiment can include heat stabilizer and light stabilizer. The function of heat stabilizer is mainly to improve the thermal stability of product, prevent decomposition and deterioration under high temperature. The function of light stabilizer is mainly to improve the light stability of product, by capturing free radicals generated by light, interrupting the chain process of photooxidation reaction, and inhibiting the degradation of material.

[0054] End-capping agent can be used to react with the active functional groups of the polymer chain end, make it lose activity, and terminate the chain growth reaction. In the preparation process of thermoplastic polyamide elastomer, there may be carboxyl, hydroxyl, isocyanate groups in the hard segment and soft segment chain ends, which can continue to participate in the reaction under the conditions of adaptation, and the activity of these active groups can be eliminated after adding end-capping agent. The end-capping agent of the present embodiment can include diprotic acid, diamine and isocyanate, which can be selected according to the type of hard segment and soft segment chain end active groups, and the addition amount of end-capping agent can also be adjusted according to the demand for molecular weight, and the present embodiment does not specifically limit this.

[0055] The antioxidant can delay the oxidation of the thermoplastic polyamide elastomer and extend the service life of the diaphragm 120. The antioxidant of this embodiment can include at least one of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant RD, antioxidant AW, antioxidant DD, antioxidant BLE, antioxidant 4010, 4010NA, 4020, 4030, 4040, antioxidant DNP, antioxidant H, antioxidant A, antioxidant D, antioxidant SP, antioxidant 264, antioxidant 2246, antioxidant 2246-S, antioxidant NBC, antioxidant MB, etc.

[0056] The ultraviolet light absorber can prevent ultraviolet light from damaging the material by absorbing the energy of ultraviolet light and converting the absorbed energy into heat or light. The ultraviolet light absorber of this embodiment includes at least one of salicylate, benzophenone, benzotriazole, substituted acrylonitrile, triazine and hindered amine.

[0057] The molecular weight regulator has a large chain transfer constant and a strong chain transfer ability. A small amount of the molecular weight regulator can be added to the polymerization system to significantly reduce the molecular weight. The molecular weight can be controlled by changing the amount of the molecular weight regulator. The molecular weight regulator of the present embodiment can include a dicarboxylic acid. The amount of the molecular weight regulator can be selected according to the requirement for the molecular weight of the thermoplastic polyamide elastomer.

[0058] The catalyst can be used to accelerate the polymerization rate of the thermoplastic polyamide elastomer. The catalyst of this embodiment can include a metal catalyst and an amine catalyst. For the metal catalyst, the catalytic effect may vary depending on the metal type and reaction conditions, and can be selected according to the reaction system.

[0059] In some practicable embodiments, the diaphragm 120 is formed by compression molding, air pressure molding or one-piece injection molding. Compression molding refers to a molding method in which a material is placed in a mold cavity at a molding temperature, and then the mold is closed and pressurized to form and solidify it. Air pressure molding refers to a molding method in which compressed air is used as a molding pressure to form and solidify the material. One-piece injection molding refers to a molding method in which molten material is injected into a mold cavity with high pressure at a certain temperature, and the finished product is obtained by cooling and solidifying. The diaphragm 120 of this embodiment can be formed by the above-mentioned multiple methods, with a high degree of selectivity, which is conducive to the control of production costs.

[0060] In some embodiments, the diaphragm 120 is formed as a single-layer structure, and the diaphragm 120 includes a layer of the thermoplastic polyamide elastomer layer A; or, the diaphragm 120 is formed as a multi-layer composite structure including the thermoplastic polyamide elastomer layer A and a connecting layer B, and the connecting layer B includes at least one of a glue layer, a thermoplastic plastic layer, a thermoplastic elastomer layer, and a rubber layer.

[0061] The diaphragm 120 may be a single-layer structure. Figure 1 is a cross-sectional view of a single-layer diaphragm, such as Figure 1 As shown, the diaphragm 120 includes a thermoplastic polyamide elastomer layer A. The single-layer structure has a simple process and a high process yield, and has an obvious cost advantage.

[0062] The diaphragm 120 may also be a multi-layer composite structure, including a thermoplastic polyamide elastomer layer A and a connecting layer B. The multi-layer composite structure can give play to the advantages of different types of materials, and the thermoplastic polyamide elastomer layer A and the connecting layer B complement each other to achieve performance optimization. The connecting layer B may include at least one of a glue layer, a thermoplastic plastic layer, a thermoplastic elastomer layer, a rubber layer, and the like. The number of membrane layers included in the multi-layer composite structure may be 2 to 8 layers, and may be prepared by processes such as hot pressing composite, multi-layer co-extrusion or hot pressing molding. Among them, the glue layer has higher damping characteristics, the thermoplastic plastic layer has higher heat resistance and strength, etc., the thermoplastic elastomer layer takes into account both strength and damping, etc., and the rubber layer has higher temperature resistance and resilience, etc.

[0063] In some embodiments, the adhesive layer includes at least one of acrylic adhesive, silicone resin adhesive, polyurethane adhesive, unsaturated polyester adhesive, epoxy resin adhesive, polyvinyl acetate adhesive, etc. The thermoplastic plastic layer includes at least one of polyetheretherketone (PEEK), polyarylate (PAR), polyetherimide (PEI), polyimide (PI), polyphenyl sulfone (PPS), polyethylene naphthalate di formic acid glycol ester (PEN), polyethylene terephthalate (PET), etc. The thermoplastic elastomer layer includes at least one of polyester thermoplastic elastomer (TPEE), polyurethane thermoplastic elastomer (TPU), polyamide thermoplastic elastomer (TPAE, Polyamidethermoplastic elastomer), polystyrene thermoplastic elastomer (TPS, Thermoplastic Styrenic Elastomer), polyolefin thermoplastic elastomer (TPO, Thermoplastic Polyolefin), dynamically vulcanized rubber / thermoplastic blend type thermoplastic elastomer (TPV, Thermoplastic Vulcanizate), etc. The rubber layer includes at least one of silicone rubber, fluororubber, nitrile rubber, hydrogenated nitrile rubber, polyacrylate rubber, EPDM rubber, ethylene acrylate rubber, isoprene rubber, styrene-butadiene rubber, polyurethane rubber, etc.

[0064] The diaphragm 120 may be a two-layer composite structure. Figure 2 is a cross-sectional view of a two-layer composite structure diaphragm, such as Figure 2 As shown, the diaphragm 120 includes a thermoplastic polyamide elastomer layer A and a connecting layer B, and the connecting layer B is a thermoplastic plastic layer, a thermoplastic elastomer layer or a rubber layer.

[0065] The diaphragm 120 may also be a three-layer composite structure. Figure 3 is a cross-sectional view of a three-layer composite structure diaphragm, such as Figure 3 As shown, the thermoplastic polyamide elastomer layer A can be one of the surface layers, the middle layer is the first sub-connection layer B1, and the other surface layer is the second sub-connection layer B2. The first sub-connection layer B1 can be a glue layer, a thermoplastic plastic layer, a thermoplastic elastomer layer or a rubber layer, and the second sub-connection layer B2 is the thermoplastic polyamide elastomer layer A, a thermoplastic plastic layer, a thermoplastic elastomer layer or a rubber layer prepared in the above embodiment. It should be noted that both surface layers of the three-layer composite structure diaphragm 120 can be thermoplastic polyamide elastomer layer A, Figure 3 The figure shows only the case where the thermoplastic polyamide elastomer layer A is one of the surface layers.

[0066] Figure 4 is a cross-sectional view of another three-layer composite structure diaphragm, such as Figure 4 As shown, the thermoplastic polyamide elastomer layer A is the middle layer, one surface layer is the first sub-connecting layer B1, and the other surface layer is the second sub-connecting layer B2. The first sub-connecting layer B1 is a thermoplastic plastic layer, a thermoplastic elastomer layer or a rubber layer, and the second sub-connecting layer B2 is a thermoplastic plastic layer, a thermoplastic elastomer layer or a rubber layer. The material types of the two surface layers can be the same or different.

[0067] In some feasible embodiments, in order to further improve the performance of the diaphragm 120 in terms of strength, damping, high temperature resistance, water absorption, etc., the number of membrane layers of the multi-layer composite structure can be set to 4 to 8 layers, and the multi-layer composite structure includes at least one layer of the above-mentioned thermoplastic polyamide elastomer layer A, and the thermoplastic polyamide elastomer layer A can be arranged on the surface layer or on the middle layer.

[0068] In this embodiment, the diaphragm includes at least one layer of thermoplastic polyamide elastomer layer, the thermoplastic polyamide elastomer layer includes thermoplastic polyamide elastomer, the thermoplastic polyamide elastomer includes a hard segment and a soft segment, wherein the hard segment contains an aromatic ring and an amide bond, the soft segment is selected from at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane, and the dimensional change rate of the thermoplastic polyamide elastomer layer after heat treatment at 120°C for 1h is ≤2%. The hard segment contains an aromatic ring and an amide bond, and the presence of the aromatic ring can largely ensure the high temperature resistance and mechanical strength of the material, effectively play the role of a physical cross-linking point, reduce the slip and viscous flow between molecular chains when the diaphragm is deformed, and the polarity of the hard segment is further increased by the coordination of the amide bond, and the interaction between the molecular chains of the hard segment is enhanced, so that the diaphragm has better dimensional stability, weather resistance and other excellent properties, and the soft segment includes at least one of polyether, polyester, polyether ester, polysiloxane, and aliphatic polycarbonate with excellent flexibility, which can provide the diaphragm with the required toughness, low temperature resistance, resilience, etc. , the soft segment and the hard segment are combined, and the thermoplastic polyamide elastomer layer shows a dimensional change rate of ≤2% after heat treatment at 120°C for 1h, which means that the thermoplastic polyamide elastomer has good dimensional stability under high temperature conditions and can withstand high temperatures. Therefore, the diaphragm provided by the present invention can combine the strength and toughness required for vibration, and at the same time has excellent properties such as good high temperature resistance and high rebound rate, which effectively solves the problems of insufficient elasticity and insufficient temperature resistance of the diaphragm in the prior art. Compared with the diaphragm made of rubber material, the diaphragm in the present invention also has the advantages of being easier to process and having low processing cost.

[0069] The present invention also discloses a sound generating device 100, referring to Figure 5 , the sound generating device 100 includes the diaphragm 120 as described above.

[0070] In this embodiment, the sound-generating device 100 may be a speaker. For example, referring to Figure 5 , Figure 5 1 is an exemplary cross-sectional view of a sound-generating device 100 in an embodiment of the present invention, wherein the sound-generating device 100 comprises a housing 110, a vibration system disposed in the housing 110, and a magnetic circuit system 140 coordinated with the vibration system, the vibration system comprises a diaphragm 120 and a voice coil 130 coupled to one side of the diaphragm 120, and the magnetic circuit system 140 drives the voice coil 130 to vibrate so as to drive the diaphragm 120 to make a sound. When the sound-generating device 100 is working, an electrical signal is input into the voice coil 130, and the voice coil 130 is driven by the magnetic field force of the magnetic circuit system 140, and moves with different amplitudes and directions as the signal size and the positive and negative directions change alternately, thereby driving the diaphragm 120 to vibrate and make a sound, so as to complete the process of converting electrical energy-mechanical energy-acoustic energy.

[0071] Optionally, refer to Figure 6 , the diaphragm 120 may include a first diaphragm 121 and a second diaphragm 122. The sound-generating device includes a magnetic circuit system 140 and a vibration system; the vibration system includes a voice coil 130, a first diaphragm 121 and a second diaphragm 122; the first diaphragm 121 and the second diaphragm 122 are respectively arranged at two axial ends of the voice coil 130, one end of the voice coil 130 drives the first diaphragm 121 to vibrate and generate sound, and the other end of the voice coil 130 is connected to one end of the second diaphragm 122 to balance the vibration of the voice coil 130, and the first diaphragm 121 and / or the second diaphragm 122 are the diaphragms described above.

[0072] The sound-generating device provided by the present invention solves the technical problem that the current diaphragm cannot meet the requirements of resilience, high strength, high temperature resistance and easy processing. Compared with the prior art, the beneficial effects of the sound-generating device provided by the embodiment of the present invention are the same as the beneficial effects of the diaphragm of the above embodiment, which will not be described in detail here.

[0073] Furthermore, the present invention also discloses an electronic device, which includes the above sound-generating device 100.

[0074] In this embodiment, the electronic devices include mobile phones, laptop computers, tablet computers, VR (Virtual Reality) devices, AR (Augmented Reality) devices, TWS (True Wireless Stereo) headphones, smart speakers, smart wearable devices, etc.

[0075] The electronic device provided by the present invention solves the technical problem that the diaphragm in the existing electronic device cannot meet the requirements of resilience, high strength, high temperature resistance and easy processing. Compared with the prior art, the beneficial effects of the electronic device provided by the embodiment of the present invention are the same as the beneficial effects of the sound-generating device in the above embodiment, which will not be described in detail here.

[0076] The diaphragm of the present invention is described in detail below with specific embodiments and comparative examples. It is worth noting that the following description is only exemplary and not a specific limitation of the present invention.

[0077] Example

[0078] A thermoplastic polyamide elastomer with PA6T as the hard segment and polyether as the soft segment is made into a thermoplastic polyamide elastomer layer with a thickness of 15μm. The thermoplastic polyamide elastomer layer is used as two surface layers, and a 15μm thick acrylic pressure-sensitive adhesive layer is used as the middle layer. Through lamination, molding, cutting and other process steps, a three-layer composite structure diaphragm with a certain shape is prepared.

[0079] Comparative Example

[0080] Polybutylene terephthalate is used as the hard segment and polyether is used as the soft segment to make a thermoplastic polyester elastomer layer with a thickness of 15 μm. The thermoplastic polyester elastomer layer is used as the two surface layers, and a 15 μm thick acrylic pressure-sensitive adhesive layer is used as the middle layer. After lamination, molding, cutting and other process steps, a three-layer composite structure diaphragm with a certain shape is prepared.

[0081] It should be noted that the hardness of the embodiment and the comparative example at room temperature is similar. The material properties and acoustic properties of the embodiment and the comparative example are compared.

[0082] Figure 7 It is the storage modulus test result figure of embodiment and comparative example, Figure 7 It can be seen that when the temperature is higher than 150°C, the modulus of the comparative diaphragm decreases significantly. It can be seen that when the temperature is higher than 150°C, the strength of the comparative diaphragm is insufficient and it is easily deformed by external forces. The embodiment diaphragm shows high temperature resistance. Even when the temperature rises to 200°C, the modulus of the embodiment diaphragm remains above 10MPa. It can be seen that the embodiment diaphragm has a strong ability to resist deformation at high temperatures and has high strength. The temperature at which the storage modulus is 6.47MPa is taken as the softening temperature, and the data is recorded in the following Table 1.

[0083] Table 1

[0084] Solution No. Softening temperature / ℃ Dimensional change rate / % Example 223 0.3～0.8 Comparative Example 171 0.5～1.5

[0085] Evaluation method of dimensional change rate: Place a material of a certain shape on a carrier with a smooth surface, place it in a 120°C oven for heat treatment for 1 hour, and record the dimensions (length or width) before and after treatment. Dimension change rate = dimensional change before and after treatment / dimension before treatment*100%.

[0086] It can be seen from Table 1 that the diaphragm of the embodiment has a higher softening temperature and a lower dimensional change rate. Figure 7 The modulus test results of the embodiment diaphragm and the comparative diaphragm at different temperatures shown further confirm that the embodiment diaphragm has obvious advantages in high temperature resistance, which is strongly correlated with the presence of aromatic rings and amide bonds in the hard segment of the embodiment diaphragm.

[0087] The embodiment diaphragm was assembled into a loudspeaker to obtain a loudspeaker including the embodiment diaphragm. The comparative example diaphragm and the embodiment diaphragm were subjected to the same operation to obtain a loudspeaker including the comparative example diaphragm.

[0088] Figure 8 is a schematic diagram of the vibration system of the loudspeaker, such as Figure 8 As shown, the diaphragm 120 is composed of a folding ring portion 123 and a spherical top portion 124 , and the thermoplastic polyamide elastomer layer A may be located at the folding ring portion 123 of the diaphragm 120 , or at the folding ring portion 123 and the spherical top portion 124 . Figure 8 The structure can be adjusted accordingly according to actual product requirements. For example, the folded ring portion 123 can protrude in a direction away from the voice coil 130, or the folded ring portion 123 can protrude in a direction close to the voice coil 130, the ball top portion 124 can be located on the upper surface of the folded ring portion 123, or the ball top portion 124 can be located on the lower surface of the folded ring portion 123, etc.

[0089] The assembled speakers were tested for high temperature life reliability. The test conditions were: voltage corresponding to product temperature of 140°C, ambient temperature of 70°C, input pink noise signal, and power on for 168 hours at 3KHz fixed frequency. The acoustic performance of the product was tested before and after reliability.

[0090] The test results are as follows: the F0 of the speaker after reliability in the comparative example is increased by 34 Hz ​​compared with the F0 before reliability, and the F0 of the speaker after reliability in the embodiment is increased by 15 Hz compared with the F0 before reliability. Fig. 9 4 is a diagram showing the high temperature life reliability test results of the loudspeaker of the embodiment and the loudspeaker of the comparative example. Fig. 9As shown, the THD (Total Harmonic Distortion) of the speaker in the embodiment does not change much before and after the reliability test, while the THD of the speaker in the comparative example increases significantly after the reliability test. When the product is disassembled, it is found that the shape of the diaphragm of the speaker in the comparative example is deformed. From the above results, it can be seen that the improvement of the high temperature resistance of the embodiment contributes greatly to the high temperature life reliability of the speaker, which can ensure the stable vibration state of the speaker at high temperature and maintain dimensional stability, thereby achieving stable performance.

[0091] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A diaphragm, characterized in that: The diaphragm includes at least one thermoplastic polyamide elastomer layer, the thermoplastic polyamide elastomer layer includes a thermoplastic polyamide elastomer, the thermoplastic polyamide elastomer includes a hard segment and a soft segment, wherein the hard segment contains an aromatic ring and an amide bond, and the soft segment includes at least one of polyester, polyether, polyether ester, aliphatic polycarbonate or polysiloxane, and the dimensional change rate of the thermoplastic polyamide elastomer layer after heat treatment at 120°C for 1 hour is ≤2%.

2. The diaphragm according to claim 1, characterized in that The hard segment includes a semi-aromatic amide structure; And / or, the mass proportion of the hard segment in the thermoplastic polyamide elastomer is 5 to 95%.

3. The diaphragm according to claim 1, characterized in that The prepolymer of the hard segment is an aromatic amide prepolymer terminated with terminal groups; Alternatively, the prepolymer of the hard segment is an amide prepolymer formed by the reaction of aromatic isocyanate and aliphatic carboxylic acid.

4. The diaphragm according to claim 3, characterized in that: The hard segment includes at least one of PA6T, PA4T, PA9T, PA10T, PA12T, PA6T / 6I, PA6T / 66, PA66 / 6T / 6I, PA10T, PA10I, PPTA, PMIA, PA5T, PA11T and PAMXD6.

5. The diaphragm according to claim 1, characterized in that: The soft segment includes at least one of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone, aliphatic polycarbonate diol, polydimethylsiloxane, polytrimethyl glycol, polyethylene oxide, polypropylene oxide diol, and polyether diamine.

6. The diaphragm according to claim 1, characterized in that: The softening temperature of the thermoplastic polyamide elastomer layer when the storage modulus is 6.47 MPa is greater than or equal to 130° C.; And / or, the moisture absorption rate of the thermoplastic polyamide elastomer layer under the conditions of a temperature of 23° C. and a humidity of 50% is ≤5%.

7. The diaphragm according to claim 1, characterized in that The thickness of the thermoplastic polyamide elastomer layer is 5 to 500 μm.

8. The diaphragm according to claim 1, characterized in that: The thermoplastic polyamide elastomer layer further comprises at least one of a stabilizer, a capping agent, an antioxidant, an ultraviolet light absorber, a molecular weight regulator and a catalyst.

9. The diaphragm according to claim 1, characterized in that: The diaphragm is molded by compression molding, air pressure molding or integral injection molding.

10. The diaphragm according to any one of claims 1 to 9, characterized in that: The diaphragm is formed into a single-layer structure, and the diaphragm includes a layer of the thermoplastic polyamide elastomer; Alternatively, the diaphragm is formed as a multilayer composite structure including the thermoplastic polyamide elastomer layer and a connecting layer, and the connecting layer includes at least one of a glue layer, a thermoplastic plastic layer, a thermoplastic elastomer layer, and a rubber layer.

11. A sound-generating device, characterized in that: The sound generating device comprises the diaphragm according to any one of claims 1 to 10.

12. The sound generating device according to claim 11, characterized in that: The sound-generating device includes a magnetic circuit system and a vibration system, the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm are respectively arranged at the two axial ends of the voice coil, one end of the voice coil drives the first diaphragm to vibrate and produce sound, the other end of the voice coil is connected to one end of the second diaphragm to balance the vibration of the voice coil, the first diaphragm and / or the second diaphragm is the diaphragm according to any one of claims 1 to 10.

13. An electronic device, characterized in that: The electronic device comprises the sound generating device according to claim 11 or 12.

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